The low levels at which vinblastine and vincristine are produced naturally by Catharanthus roseus has prompted researchers to investigate the feasibility of using in vitro techniques to produce these pharmaceutically active compounds.
As a result of research in various areas, it is now generally understood that the monomeric alkaloids catharanthine and vindoline are the components which couple, in vivo, to form an intermediate compound 3',4'-anhydrovinblastine which is converted ultimately to form vinblastine. In turn, vincristine is generated from vinblastine. The overall reaction scheme can thus be represented as follows: EQU vindoline+catharanthine.fwdarw.3',4'-anhydrovinblastine.fwdarw.vinblastine. fwdarw.vincristine
To permit economical in vitro production of vinblastine and vincristine, efficient production of 3',4'-anhydrovinblastine (hereinafter referred to as AVLB) is necessary. The present invention is therefore concerned with a method of recovering AVLB for use particularly in the application of in vitro methods for producing the more valuable dimeric alkaloids vinblastine and vincristine.